Refactor API version switching logic

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

compose/cli/command.py

@@ -13,6 +13,7 @@ from requests.exceptions import SSLError
 from . import errors
 from . import verbose_proxy
 from .. import config
+from ..const import API_VERSIONS
 from ..project import Project
 from .docker_client import docker_client
 from .utils import call_silently
@@ -77,7 +78,10 @@ def get_project(base_dir, config_path=None, project_name=None, verbose=False):
     config_details = config.find(base_dir, config_path)
     project_name = get_project_name(config_details.working_dir, project_name)
     config_data = config.load(config_details)
-    api_version = '1.21' if config_data.version < 2 else None
+
+    api_version = os.environ.get(
+        'COMPOSE_API_VERSION',
+        API_VERSIONS[config_data.version])
     client = get_client(verbose=verbose, version=api_version)
 
     return Project.from_config(project_name, config_data, client)

compose/cli/docker_client.py

@@ -11,8 +11,6 @@ from ..const import HTTP_TIMEOUT
 
 log = logging.getLogger(__name__)
 
-DEFAULT_API_VERSION = '1.21'
-
 
 def docker_client(version=None):
     """
@@ -23,8 +21,7 @@ def docker_client(version=None):
         log.warn('The DOCKER_CLIENT_TIMEOUT environment variable is deprecated. Please use COMPOSE_HTTP_TIMEOUT instead.')
 
     kwargs = kwargs_from_env(assert_hostname=False)
-    kwargs['version'] = version or os.environ.get(
-        'COMPOSE_API_VERSION',
-        DEFAULT_API_VERSION)
+    if version:
+        kwargs['version'] = version
     kwargs['timeout'] = HTTP_TIMEOUT
     return Client(**kwargs)

compose/const.py

@@ -15,3 +15,10 @@ LABEL_SERVICE = 'com.docker.compose.service'
 LABEL_VERSION = 'com.docker.compose.version'
 LABEL_CONFIG_HASH = 'com.docker.compose.config-hash'
 COMPOSEFILE_VERSIONS = (1, 2)
+
+API_VERSIONS = {
+    1: '1.21',
+
+    # TODO: update to 1.22 when there's a Docker 1.10 build to test against
+    2: '1.21',
+}